Light-colored floor covering and process of making same



Dec. 9, 1930. c. ELLIS 0 v LIGHT COLORED FLOOR COVERING AND PROCESS OF MAKING SAME Filed Dec. 2, 1926 TEXTURED SUFFACE WITH HRRDENF-D FRRGMENTS OR ETC.

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IIIIII/IIII BASE Patented Dec. 9, 1930 UNITED" STATES PATENT. oFFicE' .OARLETON ELLIS, OF MONTCLAIR, NEW JERSEY, ASSIGNOB TO ELLIS-FOSTER COMPANY,

A CORPORATION NEW JERSEY LIGHT-COLORED FLOOR COVERING AND PROCESS OF MAKING SAME Application filed December 2, 1926. Serial m. 152,308.

This invention relates to floor coverings containing a cellulose ether or ester as the primary or essential plastic and binding agent, and relates particularly to floor coverings containing n trocellulose.

In the preferred form of the invention a plastic tread composition is applied to a supporting web or fabric. Such a support or backing preferably is paper or sheets of pulp material, but in some cases, and for more expensive products, cloth burlap, and the like, may be ut lized.

In the drawing there is shown illustrative- 'ly, and not by way of limitation, a section through a fioor covering made in accordance with the present invention.

The paper material does not need to be prepared from high grade expensive fibre,

but may be made from ground wood, with perhaps some addit on of sulphite fibre, and the like, to add strength. Various cheap fibres may be employed since the paper backing is practically concealed, being in contact with the floor. The paper may be dyed,

in different colors, if desired, so as to correspond in tone with that of the tread composition, or may be of'anyother shade. Preferably such paper is rendered water resistant. This does not mean that it is necessarily absolutely waterproof, but a suflicient amount of a waterproofing agent, preferably is present, to preclude disintegration in case the floor becomes wet or when the floor covering is used in a damp locality that absorption I of moisture will not cause any undue swelling of the paper backing with consequent distortion or buckling. I

In some cases asphalt-saturatedpaper of a grade known as felt may be employed. This saturated felt is highly water resistant, but has the disadvantage when white or delicately tinted floor coverings are desired, of soiling the tread composition or throwing it off shade. This is due to small particles of the black material working into the tread composition from the rolls usually employed for sheeting. Even a small amount of'black .particles or exudations from the saturated felt may alter the color undesirably. There-.

fore, as stated, for light colored floor coverpaper is obtained, which although containing and 1,607 ,552 all of November 16, 1926.

cushioning effect and I preferably rely on the tread composition applied to the paper to While I of screens or felts employed in making the ing's, I preferably do not employ a paper backing saturated with black materials.

A suitable paper for backing purposes made from ground wood and sulphite pulp carries some rosin size .to give strength and wax-particles preferably introduced into the paper by adding dispersions or emulsions of paraflin wax or other waxes to the pulp in the beater eng ne. In this way a wax-sized but a small amount of Wax, say from 1 to 5 per cent, is quite water resistant. Paper appropriate for the foregoing purpose is described in U. S. Patents Nos. 1,607 ,517 8-9 Thin paper preferably is used for the backing, and in order to avoid spl tting ofv laminations, enough rosin size or other binder should be present to cause the fibres to adhere tightly. Papers of the kraft type are useful when: waterproofed in the manner aforesaid. I prefer to use a thin paper for several reasons. In the first place the paper itself does not afford any great amount of obtain such a cush oning quality. In the second place a heavy paper, unless saturated with some material like asphalt or pitch, is prone to expand when in a moist place and cause buckling. A paper which is only thick or stiff enough to be passed through the sheeting rolls and receive a layer of tread composition is sat sfactory and does not introduce any objectionable amount of paper stock into the product.

have thus stated the preferred form of the invention, I do not wish to be limited to the employment of such thin paper, but may use thick papers as opcasion requires and may employ saturated felt as conditions warrant. J Preferably the paper has aroug h texture or open surface, for example, showing marks paper, preferably being uncalendered or only lightly calendered and preferably being free from oily substances or such a quantity of Waxes as would serve to repel the nitrocellulose. tread composition and prevent proper adherence. It is important that the paper backing does not-at any time peel away from the tread. Nitrocellulose does not adhere well to surfaces oiled with, for example, mineral oil. It does not adhere well to a waxed surface, but by employing a wax emulsion in making the paper, and having the latter possess a fairly rough surface, adequate adherence of the tread composition results. The repellent effect of nitrocellulose on wax is recognized, and I believe the employment by me of waxed paper to which a nitrocellulose composition will actually adhere constitutes a novel feature-in the floor covering industry.

A suitable paper may be made from ground wood and sulphite pulp as aforesaid, having a thickness of about mm. and containing 2 or 3 per cent of rosin size, and from 1 to 5 per cent of wax size.

The paper may carry various fireproofing salts or substances having a fireproofing and waterproofing effect, as for example, hydrated calcium sulphate, some of the highly chlorinated compounds of benzol or naphthalene, chlorinatedepetroleum asphalt, and

the like. Any substances to go into the paper for fireproofing or for other reasons should not have a harmful effect on nitrocellulose. For example, the latter is affected by alkaline substances and therefore it is not desirable to have any condition of alkalinity which will have an objectionable effect on the nitrocellulose contacting with the paper surface.

As a floor covering should rest fiat on the floor and as thick paper is liable to curl, the employment not only of thin paper, but of paper impregnated with substances which render it more flexible or pliable, or which absorb moisture and keep the paper from becoming bone dry sometimes are desirable.

. Salts such as calcium chloride or magnesium chloride are hygroscopic and also have some fireproofing qualities. Glycerine and glycol likewise may be employed for such special result. The paper may be impregnated with resins which do not have any objectionable discoloring effect on the tread material and which afford more waterproof products. In some cases certain vegetable oils, and the like, may be introduced into the paper structure.

The tread composition may be applied to the paper backing in various ways, but I prefer applying it with the aid of sheeting rolls. These are of the type used in milling rubber and for calendering' purposes. Preferably diflerential rolls are employed, that is, one roll runs slightly faster than the other. These sheeting rolls may be set to feed the paper horizontally through them or their position may be altered so the paper feeds vertically down through the rolls or otherangles of feed may be employed.

The composition emplo ed for sheeting preferably is'of a putty-1i e consistency, or even slightly stiffer than putty. When a mass of it is squeezed in the hand preferably liquid should not exude nor should it stick very readily to the hands. Preferably it should be as dry as is consistent with applying it to the sheet of paper in a smooth layer. Such a putty-like product when made according to the preferred form of the invention has nitrocellulose as the primary cementing or binding agent, incorporated with plasticizer and filling material preferably of a fibrous character.

Antacid materials may also be present and in many cases I prefer to employ a certain proportion of volatile solvent, as'will be more fully hereinafter set forth.

The sheet of paper is fed through the rolls and while it progresses the plastic tread material is placed on the paper before the rolls and as paper and plastic pass therethrough, the tread composition is squeezed tightly into contact with the paper and thus forms the tread surface.

Such tread surface may be further rolled or calendered while still plastic to smooth the surface, or to disturb it in order to give texture, all depending on the character of .the surface finish desired.

In some cases it is possible to extrude a sheet of the tread composition and permit it to fall on a traveling sheet of paper, the latter serving as a backing either temporary or permanent. In other cases, especially when a high proportion of binder is present, it is possible to eliminate the paper backing entirely.

Floor coverings of the linoleum type as made today, have a smooth surface. This gives a severe kitchen-like effect and limits the applications of linoleum to a very considerable degree. On the other hand, roughfinished textured efiects would afford a type of fioor covering of much greater artistic possibilities than the harsh smooth and even glossy surfaces of the present day linoleum, Congoleum, and so forth.

A suitably textured fioor covering may made from nitrocellulose, as will be hereinafter more fully described.

Light colored effects have an important field of application. A pure white floor covering is desired because of its sanitary appearance. Rubber, boiled oils, and resins such as are employed in present day floor coverings makeit difficult to obtain a pure white. Using nitrocellulose, it is possible to obtain a practically pure white tread. Having such a pure color, it is then possible to add various tints and obtain new effects, for example, soft green, rose, pastel shades, and the like, which are not obtainable if the ground color is not pure white. This, if coupled with the aforesaid textured effect, enables floor rugs to be made, which because of their artistic appearance, may be used in the home or in hospitals, public buildings and the like in a widespread manner.

' The procedure therefore overcomes the kitchen-like severity of ordinary linoleum and yields new decorative effects of great possibilities.

Having obtained a white orlight-colored background it becomes possible to introduce into the sheeting small masses of other and more intense colors and thus obtain mottled or variegated color effects. This result may be obtained by adding small particles of colored tread composition to the mass of the main tread composition as it is' passing through the sheeting rolls. A better procedure is to sheet the main tread composition on the paper backing and as it emerges from the sheetirig rolls to scatter small masses of colored tread composition over the moist surface and allow the sheet to pass through a second set of rolls, thereby rolling the colored masses into the tread and. squeezing such masses over the surface to distribute them in a variegated manner. Thus, innumerable multi-colored or polychrome effects may be obtained.

If desired, instead of using two sets of rolls there may be a plurality of rolls and different colored masses added between the different rolls, all while the light-colored ground mass of the tread is sufiiciently'moist and plastic.

Using a white ground, for example, and addingsmall particles of green plastic composition, will give a product with a white hackground and splotches or streaks of green. In

a similar manner white and rose,or white and black combinations may be secured.

The addition of such supplemental colors is not as well carried out on a single set of rolls, that is, conducting the operation of sheeting and coloring all on one set of rolls as by the use of auxiliary r'olls. There is a greater tendency when using a single set of rolls in getting some of the coloring compositions so much mixed in with the main tread composition that the latter becomes simply discolored andthe well defined mottled effects desired are not produced in the same satisfactory manner. Purity of the ground tone color is highly important and the present invention makes it possible to secure technical results of the character specified through the availability of such pure ground colored tread composition. 0 v

In some cases also it is proposed to extrude onto a light-colored tread composition tiny streams of composition of a stronger color and causethe sheeting to pass through a second set of rolls, whereby the extruded material is impressed into the main tread composition. This enables stripes of color to be obtained. If the extruding tubes are given a lateral movement while the sheeted material is fed forward, the stripes will have an undulating character.

Again, it is possible to reverse the color effect and to apply lighter colored material in small proportion to a dark pigment.

In making the plastic composition I may employ nitrocellulose of high viscosity or of low viscosity, or may use mixtures of these. Also, it is possible to use scrap celluloid and other nitrocellulose waste or products which may not be suited for other purposes, as for example, to make smokeless powder. Since a floor covering contains nitrocellulose distributed through a large amount of filler, and since it is possible to have in such filler an abundance of antacid material such as zinc oxide, chalk, magnesium oxide, magnesium carbonate, and the like, nitrocellulose that might be considered dangerous if used in some directions is available for makingfloor coverings. There is therefore an outlet for low grade cellulose for the present purpose. Nitrated wood and other analogous nitrocelluloses may be used in whole or in part. Preferably I'employe celluloid nitrocellulose, or what is termed celluloid cotton as the binding agent. This has great toughness and a viscosity which is desirable in some sheeting operations. The viscosity reckoned in terms of lacquer Viscosity is approximately or seconds, or maybe higher, for example, seconds. Nitrocellu lose having a viscosity of 4 or 5 seconds also may be used.

With the celluloid cotton or nitrocellulose I preferably employ a plasticizer such as dibutyl or diamyl phthalate, aceti'n, triphenyl and tricresyl phosphates. The tricresyl phosphate is especially desirableas a plasticlzer because of its tendency to render nitrocellulose slow burning. porating a sufficient amount of the tricresyl phosphate along with a substantial proportion of mineral filler and possibly using some chlorinated hydrocarbon to saturate the paper backing a relatively and notably fire resistant floor covering may be obtained.

Castor oil orcrapeseed oil, preferably of the blown type, sometimes may be added to the composition to yield greater flexibility.

A floor covering or rug which flattens effectively is obtained desirably by incorporation with the celluloid cotton or other By incornitrocellulose of a quantity of an appropri- Most natural resins shorten the life of nitrocellulose coatings, whereas, the resins aforesaid act as preservatives. However, I do not wish to exclude additions of natural resins or of various natural resins which have been modified by chemical treatment, as for exj ample, rosin ester;

The above resins which have the compatible properties noted may be added-in considerable proportion to assist in obtaining a non-curling rug. By employing a goodly proportion of plasticizing material and soft -compatible synthetic resin, the desired flattening effect may be secured.

As pigment there may be used-for white sheeting such substances as lithopone, zinc oxide, white lead, sublimed lead, lead sulphate, barytes, chalk, and the like. Titanox is also a strong white, but is not wholly a pure white, and in some cases has been observed to have an action on nitrocellulose. Some 7 of the pigments have an antacid effect which is desirable. Colors or pigments are added to tint as desired.

Q Certain mineral substances such as calcium sulphate containing the maximum amount of water of hydration are .desirable as fillers because they tend to reduce the inflammability in a Very marked way.

In addition to themineral antacids I may use organic antacids such as urea or amines.

" The character of the fibrous material employed as filler is important as on this to a certain extent depends the strength and flexibility of the tread and its cushioning effect. Asbestos fibre, ground wood, sulphite pulp, and the like, may be used, according to the character of the floor covering desired. WVhen a cream colored finish or darker effect is wanted, ground cork of a fineness passing say 608O mesh is useful.

For a white textured effect a considerable proportion of cotton flock, linters, bleached sulphite pulp, and the like, may be used.

The greater the proportion of material such as cotton flock, employed, the more textured, as a rule, will be the surface. 'In passing through the rolls the cotton flock gathers to some extent and sets irregularly,'giving a rip- 'pled o'r flow-marked surface, or what may be acetates, diacetone alcohol, ethyl lactate, butyl propionate, and so forth. Using these highboiling solvents allows plenty of time to work out the composition on the rolls and the masses of material on hand do not dry out so quickly that their use in a commercial way becomes unfeasible.

However, such high boiling solvents are more expensive than some of the more volatile solvents. Acetone, for example, is much cheaper and is a very powerful solvent for nitrocellulose. Furthermore, acetone solu tions have a viscosity lower than those made with some of the high boiling solvents. This is sometimes advantageous in securing a good sheeting effect. Methyl acetone also may be used, likewise, methyl and ethyl acetate. Is-

.orpropyl acetate is not as powerful a solvent,

but may be-used to advantage as it is fairly cheap. Associated with the nitrocellulose solvents may be various diluents for the sake of cheapness, as for example, benzol and toluol,

" light petroleum benzine, monochlorobenzol,

and the like.

However, the employment of such cheap highly volatile solvents brings with it the difficulty that the masses of material on hand in the workroom dry out too quickly, besides giving off a large amount of vapors which pollute the air. To obtain a workable composition which remains plastic for an indefinite period, I introduce a small amount of a mineral wax, as for example, ceresin or paraffin wax, This gives to the composition two very.

useful qualities. In the first place, it does not dry out quickly at room temperature, but remains plastic and workable for a relatively long time. In the second place, it dries out very quickly at temperatures above, say, 100

F. Thus, it becomes possible to dry and sheet the composition very rapidly. This is not true with some of the high boiling solvents mentioned, these requiring more protracted heating. and even so, the odor sometimes is retained in athick tread composition for a long time and may be identified even after the finished rugs have been kept for some time.

For this reason the addition of wax is advantageous, since a plasticity is maintained on exposure at room temperature over a considerable period and moreover, drying when desired, takes place quickly, requiring a relatively compact drying chamber. The odor is eliminated from the goods speedily and is not retained so as to be offensive when the rug is subsequently unrolled on the floor.

Various waxes having a polishing characteristic, such as carnauba, Montan, beeswax, or shellac wax, may be added, in some cases. Hot calendering enables a more polished surface to be obtained when desired.

Sometimes it is desirable to have the solvent employed in the plastic materialof low inflammability. and in such cases I may introduce non-inflammable solvents, as for ex- 7 lull ample, carbon tetrachloride or trichlorethylene. The latter is preferable to'the former tie a solvent for nitrocellulose should be used which is not too highly inflammable. Acetone and methyl acetate are less suited than ethyl acetate, isopropyl acetate, and some of the higher esters. Mixtures of isopropyl acetate or isobutyl acetate with trichlorethylene, when incorporated with nitrocellu lose, filler, plasticizer and tricresyl phosphate, with or without a synthetic resin or preservative solid, will be found to possess very little, if any, tendency to inflame on bringing, for example, a lighted match,-near a mass of the material. If a flame is held in contact with the material for a suflicient length of time the solids themselves may take fire, but the rate of combustion is comparatively slow and the fire hazard therefore is greatly reduced. Incorporation of wax in such a composition greatly reduces the tendency to evolution of vaporsand this is desirable not only from the standpoint of fire v hazard, but because the mass of material for sheeting is maintained in a state of uniform plasticity over a considerable period.

In some cases chlorinated ethylene, that is,

ethylenedichloride, or Dutch liquid, may be used to reduce inflammability.

lVhile the desirability of using a volatile solvent, that is, quick-drying, after the completion of sheeting has been emphasized, it

' should be understood that I do not exclude sheeting with hot rolls without solyents, but with sufficient plasticizer and/or resin to obtain anadequate softening effect. Such hot sheeting cannot be carried out very satisfactorily with ordinary asphalt-saturated felt because the temperature of sheeting is usu-' ally higher than the melting point of the saturating material and the latter is'therefore squeezed out ofthe felt between the rolls.

There are cases also when water emulsions of nitrocellulose and plasticizer may be employed, using for example, bentonite as an emulsifying agent.

When it is not appropriate to produce a tread of sufficient thickness in one sheeting operation, a tread may be formed, dried and a second layer of tread composition sheeted on the first, so that there is obtained one tread layer superposed on another. This pro-v cedure may be repeated, if desired; to'obtain a plurality of'tread layers.

On the other hand, it is also feasible to sheet first on one side of" the pa er support "and then to sheet. the other si e. In this way treads opposedto 'one another are obtained and rugs or runners ma be made in this manner which are reversible. When one side has been worn out the rug is reversed and a fresh tread surface becomes available. These opposed tread layers may, if desired, be of different colors. p

One form of the invention is that in which the rugs, runners, or other forms of floor covering take for shi ment. To prepare for transportation the oor covering is rolled so that the flexible sheeting support of paperbacking is on the inside, while the tread composition faces outwardly, that is, a cross sec-- tion of the roll would show the tread of each spiral or convolution facing outwardly,

while the paper support would be facin inwardly. This, of course, applies to pro ucts.

having the tread on only one'sideof the paper backing. By rolling in this manner the tread surface'ls'maintained in a state of extension, a condition which is highly desirable, especially in the case of surfaces of rug, runner, or strips, (latter being intended to be laid in parallel, e. g. to cover a floorcompletely) said floor covering being preferably substantially self-flattening and noncurling, that is, when laid does not persist in curling upwards at the ends or corners, although not fastened to the floor. The invention also contemplates a floor covering which is slow-burning, that is, one which does not exhibit any undue fire hazard, also, one which is suificiently water-resistant to stand expo sure to such contact'with water as is likelyunder reasonable service conditions; moreover, a floor covering which preferably has a substantial cushioning effect, that is, has adequate softness underfoot due to a resilient tread of appropriate thickness; said floor covering being composed of, or comprising a flexible sheeting support, e. g., paper, waterproofed paper, waxed paper, wax-sized paper, and the like, carrying a nitrocellulose tread composition adapted for underfoot usage; such floor covering preferably having an ornamental surface secured by-the use of pleasing colors, variegated colors, textured finish, and the like.

Atextured effect such as is obtained by embossing a design by means of rolls is not as,

satisfactory as the methodof destroying the smooth continuity of the surface to obtam an In one form of the invention, a volatile solvent, or water, is present in the plastic tread composition and after sheeting this on a support, the product is rapidly heated to cause bubbles or pores to form. \Vhen this i has progressed sufficiently the sheet may be re-rolled to smooth out the surface somewhat. A more cushiony effect is obtained in this way. The combined effect of this with a resilient filler such as wood flour or ground cork is advantageous from the cushioning standpoint.

Another filling material which may be used to good advantage in making a more fire resistant product is vegetable ivory waste. This material in the form of fine fragments or dust is a by-product of the manufacture of buttons, and the like. It does not have the same combustibility as, for example, wood flour. Being very light in color it can be used freely in making light-colored and variegated products.

When paper is used as the backing material, in addition to impregnating it with ammonium phosphate and incorporating, for example, paraliin wax as a waterproofing agent, I may also use chlorinated nahptha-v lene such as the tetra or penta chloride of naphthalene, perchlorinated benzol, chlorinated asphalt, and the like, as sizing or waterproofing agents. These chlorinated compounds confer fireproof qualities as well as acting as waterproofing agents. In addition, chlorinated naphthalene, and the like, may be incorporated in the tread composition as a polishing agent and also to depress combustibility.

A feature of my invention is the employment of mineral salts containing water of crystallization or hydration. A salt which is suitable for the purpose is finely-ground r precipitated calcium sulphate containing 2 molecules water. If plaster of Paris, that is, calcined calcium sulphate, is moistened with water, it gives up more than 2 molecules water and this perhy'drated sulphate is a useful filler to employ in making tread compositions. In order to obtain fire resistance to a high degree I preferably employ a substantial proportionof the perhydrated calcium sulphate.

In some cases nitrocellulose, as for example, celluloid stock, may be used wet with 'water. This avoids drying the nitrocellulose prior to use and enables it to be stored safely and to be handled with aconsiderable degree of impunity. In using such material, if desired, a portion of the water may be absorbed by mixing calcined calcium sulphate, e. g., plaster of Paris, when this hydrated water is absorbed from the nitrocellulose and dries it to the extent corresponding to the amount ofplaster of Paris added. It is important to avoid mixing the plaster of Paris in such a manner that the nitrocellulose mass becomes heated to an objectionable degree due to the reaction of hydration.

IVhen wet nitrocellulose is employed and all the water is not absorbed by a dehydrat ing filler, the nitrocellulose may be converted into a kind of an emulsion with plasticizer and possibly a solvent such as butyl acetate or amyl acetate not miscible. with water. Additional water may be added if desired in .order that a putty-like'material results when the bulky filler is added. In other words, the water serves to replace a volatile solvent in whole or in part, to produce the puttylike sheeting composition.

When triphenyl or tricresyl phosphate is used as a plasticizer for nitrocellulose in tread compositions which are white or lightcolored, the employment of zinc oxide or certain other basic bodies as antacids may result in a slight saponification of the plastioiZer with the liberation of phenols and the possible discoloration or pigmentation 'due to such phenolic substances. This alteration,

unless of considerable extent, may be of very slight consequence with some of the variegated tread surfaces, but the case may prove quite different with an extremely light-colored or ure white tread. Plasticizers which do not ments and antacids which do not have a saponifying action on triphenyl phosphate or tricresyl phosphate may be used. In one form of the invention I contemplate using, for example, tricresyl phosphate as the principal plasticizer with pigments, fillers or antacids inert or innocuous thereto. Likewise, when synthetic resins such as those of the glyceride type mentioned above are employed, preferably a basic pigment is avoided which will saponify the resin and cause hardening or brittleness. Hence I prefer to employ pigments, fillers and antacids substantially free from destructive or hardening action on these resins.

From the foregoing it will appear that I preferably employ in tread compositions containing nitrocellulose with both synthetic resins and plasticizing agents, a type of pigment, fillers and antacids which are inert with respect to such essential substances, or, at least, have no objectionable action. Just as Iprefer to employ a synthetic resin compatible with nitrocellulose, so I prefer to employ pigments, fillers and antacids which are compatible with nitrocellulose, synthetic resins and plasticizers.

As an illustration celluloid nitrocellulose containing alcohol, used to moisten it durave any discoloring action on piged, making a white putty, which was sheet-.

ed on various forms of backing, including paper. After sheeting the moist sheeting product was dried gradually up to about 7 5 C. The solvent was rapidly removed at this temperature.

The textured effect of a very marked type was obtained by forming fragments of tread composition still plastic but dried out somewhat and applying such fragments helter skelter to a freshly' sheeted surface, then passing through rolls. The somewhat harder lumps of the drier tread composition imparted anotable texture to the surface in this manner.

Another tread composition was made from 500 parts by weight of nitrocellulose, dry weight, (moistened with denatured alcohol), 665 parts plasticizer, 400 parts acetone, and 300 parts benzol. The nitrocellulose was allowed to soak over night in the solvents and plasticizers and thoroughly mixed the fol lowing morning in a Werner-Pfleiderer mixer. There was added 750 parts cork dust, 80 mesh, 750 parts lithopone, parts chrome green. The composition also included 12%; parts ceresin wax. Finally 200 parts each of acetone and benzol were added to obtain a more plastic putty.

Large sheets of blotting paper, manila paper and saturated felt base were sheeted I with this compositionand driedv at about 45 C. When drying had progressed sufficiently a second sheeting of material was applied to the first. Good surfaces were obtained. Some of the samples. were placed in a hydraulic press in contact with a polished sheet of metal and were pressed for five minutes at 500 to 1000 lbs. pressure, the press being heated by steam at 20 lbs. pressure. This gave a very smooth surface.

In the foregoing formula it should be noted that the plasticizer is dibutyl phthalate; or a mixture of this substance and tricresyl phosphate. Or, if more fireproof results are desired, the plasticizer may be entirely tricresyl phosphate.

Variegated results are obtained, for example, by sheeting the light-colored composition set forth above and applying to the surface at irregular distances small portions of the green composition set forth in the second formula. In. this manner a two-color or mottled and streaked effect is secured.

Still another composition was prepared from:

Parts by I weight Celluloid nitrocellulose 400v Denatured alcohol 160 Tricresylphosphate 612 Acetone 320 Benzol 240 Paraflin wax 20 Urea i -1 4 Cottonseed fatty acid phthalic glyceride resin dissolved in an equal weight of volatile solvent (200 parts actual resin) 400 After thorough incorporation the following fillers were added:

Parts Cotton flock 100 l inely-dh idcd vegetable ivory 400 Per-hydrated calcium sulphate ,400

Lithopone 200 This produced a white mix. A good yellowtone was obtained by adding 20 parts chrome yellow. y

The volatile solvent'used to dissolve the synthetic resin was a mixture of equal parts toluol and secondary butyl acetate.

The composition sheeted satisfactorily on saturated felt and 011 paper which was not impregnated.

Products were obtained ranging from a heavy tread to one which was merely a veneer. The best results wlth such Veneers -were obtained with saturated felt as a cushioning support.

A glossy smooth finish was obtained by pressing the dry sheeted product. betweenpolished metal plates in a hydraulic press at 1000 lbs. pressure per square inch and at a temperature corresponding to 20 lbs. steam pressure.

In one case with a solution made from 1 part by weight blotting paper was saturated diammonium hydrogen phosphate in 2 parts v water. The paper then was dried andsome of the last mentioned tread composition was sheeted thereon to form a floor; covering product. This material could not be ignited by the flame of a'match.

Finally Iwish to emphasize the feature that in the preferred form of the invention the plastic material-when prepared for sheet-' ing is not self-supporting in thin layers of the thickness of the intended tread. Thisv is likewise true after sheeting and before elimination of volatile solvents. Drying, however, causes a cementation of the sheeted mass and strengthening of the tread. The paper or other support so needful therefore to carry the tread layer in its freshly sheeted condition becomes less important after dryand the like in hot rolling as well as other ob-- jectionable features of hot rolls, is avoided.

Using felt saturated with soft pitch or asphalt to give pliability makes hot rolling in sheeting on a veneer of nitrocellulose tread composition a matter of great practical difficulty. On the other hand the employment of highly volatile solvents anchored at room temperature 1n a tread composition by wax and readily released at slightly higher teniperatures enables such veneer to be applied quickly and cheaply. 4

Also, I wish to note that using such solvents and wax, a remarkably adherent tread results even to a paper backing containing a very considerable proportion of wax waterproofing.

The drawing illustrates in cross section a floor covering or other article of manufacture of similar character made in accordance with the present invention. As shown therein the base A, which may be a flexible paper support or wax-containing paper support, carries a tread composition B containing nitrocellulose or other compositions produced in accordance with the present invention as hereinabove set forth. The nitrocellulose tread composition carriesa textured surface produced by rolling in hardened fragments of desired plastic composition, etc., the textured surface being represented at G in the figure of the drawing.

'hat I claim is 1. As a floor covering a flexible wax-containing paper support carrying a nitrocellulose tread composition of textured white surface.

2. A process of making a floor covering comprising sheeting a light colored nitrocellulose composition upon a substantiallywaterproofed backing, and rolling thereinto hardened plastic fragments whereby a textured effect is obtained.

3. A floor covering comprising a waterresistant flexible sheeting support carrying a light colored nitrocellulose composition tread, and having rolled in hardened plastic frag- .ments yielding a textured effect.

lulose composition upon a substantially waterproofed backing, and rolling into said tured effect is obtained. 8. A floor covering comprising a waterresistant flexible sheeting support carrying a light-colored nitrocelulose composition tread, and having rolled in hardened fragments of a plasticnitrocellulose composition, whereby a textured effect is obtained.

9. A process of making a floor covering comprising sheeting a nitrocellulose tread composition upon a backing, and rolling thereinto hardened plastic fragments whereby a textured effect is obtained.

10. A floor covering comprising a flexible sheeting support carrying a. nitrocellulose.

composition tread, and having rolled thereinto hard plastic fragments yielding a textured effect.

11. A process of making a floor covering comprising sheeting a nitrocellulose tread composition hardened fragments of a plastic nitrocellulose composition, whereby a texcomposition upon a backing, and@ rolling thereinto hardened fragments of a plastic nitrocellulosecomposition whereby a textured effect is obtained.

12. A floor covering comprising a flexible sheeting support carrying a nitrocellulose composition tread, said tread carrying hard ened fragments of a nitrocellulose plastic composition pressed into the tread whereby a textured effect is obtained.

OARLETON ELLIS. 

